The article discusses the engineering synthesis of discrete-logic control systems for industrial machinery based on the algebra of logic. Given the method of designing new kinds of systems - Firmware discrete logic control systems. Projects of microprogram control systems are created in the instrumental ISaGRAF programming environment using the language of functional blocks FBD. An example of programming of the control system of tool electroautomatics in FBD is given. The main distinguishing feature of the technique of programming discrete-logical systems is that one of the main elements of the high-level language SFS in included in the FBD program. This language, in turn, is taken from microprogramming machines and provides the procedure of consecutive sample of micro-ops from the memory of the computer that allows you to extend the scope of solvable discrete-logic problems in FBD and simplifies their solution. Branching commands and calls to subroutines greatly extend the functionality of microprogram control systems created in FBD. Practical implementation of microprogram control systems for complex objects, like any other management systems, requires solving problems of a private nature arising in the design process. Graphic language of functional diagrams FBD is well suited to solve this kind of issues because functional diagrams created in the ISaGRAF project are illustrative, they are identified with real electronic circuits and therefore they are relatively easily debugged and tested by means of the tool system programming. Ultimately, in ISaGRAF function diagrams are automatically translated into application programs that are loaded in the PLC or industrial computers. Function diagrams created by means of ISaGRAF, can also be used to build discrete-logic control systems based on integrated logic circuits. In addition, functional diagrams can serve as intermediate models for discrete programming-logical systems in the algorithmic language C++.